Vendordata¶
Note
This section provides deployment information about the vendordata feature. For end-user information about the vendordata feature and instance metadata in general, refer to the user guide.
The vendordata feature provides a way to pass vendor or deployment-specific information to instances. This can be accessed by users using the metadata service or with config drives.
There are two vendordata modules provided with nova: StaticJSON
and
DynamicJSON
.
StaticJSON
¶
The StaticJSON
module includes the contents of a static JSON file loaded
from disk. This can be used for things which don’t change between instances,
such as the location of the corporate puppet server. It is the default provider.
Configuration¶
The service you must configure to enable the StaticJSON
vendordata module
depends on how guests are accessing vendordata. If using the metadata service,
configuration applies to either nova-api or
nova-api-metadata, depending on the deployment, while if using
config drives, configuration applies to nova-compute. However,
configuration is otherwise the same and the following options apply:
Refer to the metadata service and config drive documentation for more information on how to configure the required services.
DynamicJSON
¶
The DynamicJSON
module can make a request to an external REST service to
determine what metadata to add to an instance. This is how we recommend you
generate things like Active Directory tokens which change per instance.
When used, the DynamicJSON
module will make a request to any REST services
listed in the api.vendordata_dynamic_targets
configuration
option. There can be more than one of these but note that they will be queried
once per metadata request from the instance which can mean a lot of traffic
depending on your configuration and the configuration of the instance.
The following data is passed to your REST service as a JSON encoded POST:
Key |
Description |
---|---|
|
The ID of the project that owns this instance. |
|
The UUID of this instance. |
|
The ID of the image used to boot this instance. |
|
As specified by the user at boot time. |
|
The hostname of the instance. |
|
As specified by the user at boot time. |
Metadata fetched from the REST service will appear in the metadata service at a
new file called vendordata2.json
, with a path (either in the metadata service
URL or in the config drive) like this:
openstack/latest/vendor_data2.json
For each dynamic target, there will be an entry in the JSON file named after that target. For example:
{
"testing": {
"value1": 1,
"value2": 2,
"value3": "three"
}
}
The novajoin project provides a dynamic vendordata service to manage host instantiation in an IPA server.
Deployment considerations¶
Nova provides authentication to external metadata services in order to provide
some level of certainty that the request came from nova. This is done by
providing a service token with the request – you can then just deploy your
metadata service with the keystone authentication WSGI middleware. This is
configured using the keystone authentication parameters in the
vendordata_dynamic_auth
configuration group.
Configuration¶
As with StaticJSON
, the service you must configure to enable the
DynamicJSON
vendordata module depends on how guests are accessing
vendordata. If using the metadata service, configuration applies to either
nova-api or nova-api-metadata, depending on the
deployment, while if using config drives, configuration applies to
nova-compute. However, configuration is otherwise the same and the
following options apply:
Refer to the metadata service and config drive documentation for more information on how to configure the required services.
In addition, there are also many options related to authentication. These are provided by keystone but are listed below for completeness:
Refer to the keystone documentation for information on configuring these.
References¶
Michael Still’s talk from the Queens summit in Sydney, Metadata, User Data, Vendor Data, oh my!
Michael’s blog post on deploying a simple vendordata service which provides more details and sample code to supplement the documentation above.